1. Field of the Invention
The present invention relates to an electronic endoscope apparatus having a built-in endoscope light source unit that is suitable for an endoscope, or an electronic endoscope, etc.
2. Description of the Related Art
Recent electronic endoscope systems have a processor with a built-in light source unit, to which an electronic scope having an electronic camera mounted on the distal end thereof or a fiber scope for conducting observation only through optical members is connected for use. In particular, electronic scopes have been provided for use with a wide variety of thicknesses and functions suited to different locations of observation. Processors connectable with various types of electronic scopes and fiber scopes must also have light source units that are compatible with such various electronic scopes and fiber scopes. For this reason, conventional light source units have been constructed so as to supply necessary amounts of light to electronic scopes that require maximum light intensities.
Such light source units are configured such that illumination light emitted from a high-intensity lamp is condensed by a condenser lens and made incident on the incident end face of a scope light guide, typically an optical fiber bundle. Since the necessary amount of illumination light varies with the type of electronic scope and with the observation location, the light source units are equipped with an aperture device for adjusting the amount of light mechanically. Among known aperture devices is one that includes a diaphragm which is composed of a partly-notched portion and an arm portion integrated with the partly-notched portion, having such a size that all the light from a light source lamp can be blocked; and a motor mechanically connected to an end of the arm portion. The motor is rotated to turn the diaphragm about the top of the arm portion, thereby adjusting the illumination intensity (see Japanese Patent Laid-Open Publication No. 2003-305008). Moreover, a light shielding plate may be provided with a plurality of aperture openings having different opening ratios or transmittances, and which regulates the amount of light incident on the incident end face of a light guide by putting one of the aperture openings selectively between a light source unit and the incident end face (i.e., into the illumination optical path) of the scope light guide.
Conventional electronic endoscope apparatuses have a main switch for turning ON a processor power supply and a light source switch for turning ON a light source unit separately. Typically, when the main switch is turned ON, an imaging circuit is activated to drive the electronic camera of an electronic scope connected thereto, so that captured images are displayed on a monitor display.
However, when the main switch alone is turned ON, it is impossible to insert the electronic scope into a body cavity or the like since the illumination unit is not yet turned ON. Consequently, it has been necessary to make troublesome operations of turning ON the main switch as well as turning ON the light source switch.